Hi I am having problem with Domain mapping

Hello There,
I'm a newbie here and found most of your plugin working flawlessly but I'm having challenges with 'domain -mapping'. I am hosting with GD with dedicated IP and have changed the A record for tap-deal.com to point to 46.252.199.81.I have a sub-directory settings for multi-site.
My main site is cookawebsite.com (wp installed in root) and I tried using domain mapping to view site tap-deal.com/one worked fine but when I try to use tap-deal.com it takes me to cookawebsite.com .
I have looked in to domain parking but it seems its parked as there're no other option than changing the A record to point to my dedicated IP which GD (GoDaddy :wink: agrees as well.
Also may be stupid question but when I was doing the 'multi-domain' installation it was advised to re-name the dm_sunrise.php to sunrise.php in wp-content but since there're already sunrise.php (from prior installation of Domain Mapping it wasn't feasible (or is it not needed ,nor sure if I messed up any thing there) .

Please respond as I'm still being hopeful to make it work.
Thank you in advance.